fix(sandbox): require runner-specific spawn evidence

This commit is contained in:
Hypatia May
2026-08-04 14:47:46 +08:00
parent 0cd1611023
commit 96ba98c99e
14 changed files with 217 additions and 39 deletions

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@@ -17,7 +17,7 @@ Every command is confined by handing the provider the exact `['bash', '-c', comm
Semantics:
- **Denials are result facts.** A failed run whose stderr carries the selected backend's own denial dialect — the signatures the provider stamps on every wrap (EROFS text under bwrap, EACCES under Landlock, EPERM under Seatbelt) — is reported as `BashRunResult.sandbox.denied: true` (conservative classification, read from the collected stderr tail); every CONFINED run also carries the mode it executed under (`result.sandbox.mode`) and the provider's enforcement completeness (`result.sandbox.enforcement`: `full`, or `partial` on an older Landlock ABI).
- **Runner failures are sandbox failures, never command failures.** A rejected spawn of the provider argv is out-of-band proof that the confined launch never started: foreground execution throws `SANDBOX_UNAVAILABLE` with the original spawn detail, while background settlement stamps `runnerFailed: true` and `denied: false`. After a process starts, a rule's optional exit-code gate and a remaining fatal stderr line must both match after exact informational-line exclusions. A match outranks denial; foreground execution throws `SANDBOX_UNAVAILABLE` with the matched fatal line, while a settled background process stamps `process.sandbox.runnerFailed`, which the bash producer renders through generic `task_output`. Confined background handles retain their mode/enforcement facts and release per-process accounting in either path.
- **Runner failures are sandbox failures, never command failures.** Before a process starts, a spawn rejection is attributed to the runner only when its structured code and an independent lookup both show that the provider's executable is missing or unusable: foreground execution throws `SANDBOX_UNAVAILABLE` with the original spawn detail, while background settlement stamps `runnerFailed: true` and `denied: false`. Other spawn rejections retain the local executor's command-start failure semantics. After a process starts, a rule's optional exit-code gate and a remaining fatal stderr line must both match after exact informational-line exclusions. A match outranks denial; foreground execution throws `SANDBOX_UNAVAILABLE` with the matched fatal line, while a settled background process stamps `process.sandbox.runnerFailed`, which the bash producer renders through generic `task_output`. Confined background handles retain their mode/enforcement facts and release per-process accounting in either path.
- **Deployment fallback, per-call policy.** [`ctx.sandboxPolicy`](../../sandbox/sandbox-policy/) resolves a complete `SandboxExecutionPolicy` for every tool call: the calling session supplies its mode override and immutable cwd root, while deployment config supplies the fallbacks for agentless calls. An approved escalation changes only that policy's mode; its session root stays attached. `resolve()` carries the policy onto the spec, so overlapping commands from different projects run, classify, and report under their own roots and modes. The capability fact `ctx.bash.sandboxMode` reports the configured default so the tool layer advertises escalation only when this executor is mounted; the static bash tool description separately owns denial and escalation guidance.
- **File effects only.** Network and process visibility are deliberately not restricted — the mode vocabulary does not pretend to cover what the backend does not enforce.
- Process mechanics (spawn, process-group kills, output collection/spill, background handles, credential scrub) are inherited from [`dsh-bash-local`](../bash-local/); runner selection lives in [`dsh-sandbox-local`](../../sandbox/sandbox-local/).
@@ -72,7 +72,7 @@ Append-only; newly visible content follows the reusable request prefix and does
#### What the model sees
If no runner can enforce a confined mode, the foreground call propagates the [`SANDBOX_UNAVAILABLE` error owned by `dsh-sandbox`](../../sandbox/sandbox/README.md#confinement-error-indirectly). A provider-argv spawn rejection supplies the original spawn error as detail; a settled runner failure supplies the matched fatal stderr line and preserves the original stderr collection.
If no runner can enforce a confined mode, the foreground call propagates the [`SANDBOX_UNAVAILABLE` error owned by `dsh-sandbox`](../../sandbox/sandbox/README.md#confinement-error-indirectly). A provider-executable spawn failure supplies the original spawn error as detail; a rejection without runner-specific evidence remains an ordinary command-start error. A settled runner failure supplies the matched fatal stderr line and preserves the original stderr collection.
#### Token effect